The polyester fabrics which are in wide use today are produced from paraphthalic acid which is in turn produced by the oxidation of para xylene. Para xylene is typically derived from a xylene isomerization zone or from a stream separated from an aromative rich precursor, such as a C.sub.8 aromatic hydrocarbon fraction derived from a catalytic reformate by liquid-liquid extraction and fractional distillation. The para xylene is commercially separated from a paraxylene-containing feed stream, usually containing all three xylene isomers, by either crystallization or adsorptive separation or a combination of these two techniques. Adsorptive separation is the newer technique which has captured the great majority of the market share of newly constructed plants for the production of paraxylene.